New SCAI Statement on Classification of Cardiogenic Shock

Batya Swift Yasgur MA, LSW

June 13, 2019

The Society for Cardiovascular Angiography and Interventions (SCAI) has released a new consensus statement on the classification of cardiogenic shock (CS).

The statement, authored by a multidisciplinary panel of experts from specialties that included cardiac critical care, interventional cardiology, nursing, emergency medicine, and heart failure (HF), is the first-ever guideline to categorize and classify the five stages of cardiogenic shock, starting with "at risk" and moving through "beginning," "classic," "deteriorating," and "extremis."

"The statement is groundbreaking" because CS is "not one-size-fits-all, but rather has gradations and different levels of profound sickness," statement chair Srihari Naidu, MD, professor of medicine, New York Medical College, Valhalla, told theheart.org | Medscape Cardiology.

Naidu, who is also the director of the Cardiac Catheterization Laboratory and Hypertrophic Cardiomyopathy National COE, Westchester Medical Center, said the statement creates a "whole new lexicon that people can start using over the world quickly for rapid triage."

The statement was presented at the recent SCAI 2019 annual meeting and simultaneously published online May 19 in Catheter and Cardiovascular Interventions.

Common Language

Naidu said it has been "demoralizing" that "we have not moved the needle in mortality rates in CS and we have not known what patient population will have maximum benefit from different devices or therapy."

"I'm a heart failure and transplant physician who also does interventional work," Baran told theheart.org | Medscape Cardiology. "Over the years, I've watched devices evolve to take care of patients with various degrees of [cardiogenic] shock and hoped that each trial, each new device, would move the needle forward toward decreasing mortality, but each was more disappointing than the next.

"In talking to colleagues from various disciplines, we realized that there is a wide variety of different stages that have all been called 'shock,' but actually some patients only have mild hypoperfusion and hypertension while others are in much deeper shock, and there has been no common vocabulary to describe these different presentations," Baran added.

"We realized that what was missing was a system akin to the NYHA heart failure classification that would create a common language so everyone involved in that patient's care understood exactly what kind of patient was presenting."

He noted that the statement has been well received in the community.

"For example, I presented this model to more than a thousand EMS providers and they said: 'This is so simple. I can finally describe in common language what state the patient is in so everyone [involved with the patient's care] is prepared, mobilized, and can figure out what's wrong'," he said.

"Everyone can be part of the team, which was a huge goal of ours," he added.

The classification system was designed to be used beyond the United States, and to become "a standard classification used worldwide so people could communicate each other in each setting, no matter what country, and clearly understand immediately what type of patient is being described," he said.

Five Stages

The classification schema consists of five stages, which are determined by three domains: biochemical (laboratory) findings; clinical bedside findings; and hemodynamics.

"Our classification system does not legislate the presence of a particular number of findings, but instead describes the common features that are prototypical of each stage," the authors state.

"These stages are recognizable," Baran commented.

"Stage A includes a variety of disorders that place someone at risk for CS, while in stage B, patients have a high heart rate — above 100 — or low blood pressure, but are still maintaining end organ perfusion," he said.

By contrast, patients in stage C "are the 'classical' CS patients who present with abnormal perfusion, have depressed urine output, clammy skin, or signs of mental dullness — people whose cardiac output is not sufficient for demands," Baran explained.

Patients in stage D "are deteriorating, and whatever you pick doesn't work," he continued. "At stage D, the implication is a different trajectory and your train is starting to run off the tracks."

Baran called stage E "the top of the pyramid" and the "smallest minority, who are easy to recognize; there are multiple nurses and physicians in the room and the patient has a high likelihood of dying."

Five Stages of Cardiogenic Shock

Description

Physical Exam/Bedside Findings

Biochemical Markers

Hemodynamics

Stage A: At risk for CS

No signs/symptoms of CS but at risk of its development

Includes patients who may "appear well" and may even have normal laboratory findings/physical examination

Normal JVP

Clear lung sounds

Warm and well perfused

Strong distal pulses

Normal mentation

Normal labs

Normal renal function

Normal lactic acid

Normotensive

If hemodynamics done:

• Cardiac index ≥2.5

• CVP <10

• PA sat ≥65%

Stage B: Beginning CS

Clinical evidence of relative hypotension or tachycardia without hypoperfusion

Elevated JVP

Rales in lung fields

Warm and well perfused

Strong distal pulses

Normal mentation

Normal lactate

Minimal renal function impairment

Elevated BNP

SBP <90 or MAP <60 or >30 mm Hg drop from baseline

Pulse ≥100

If hemodynamics done:

• Cardiac index ≥2.2

• PA sat ≥65%

Stage C: Classic CS

Hypoperfusion requiring intervention

Relative hypotension

May include any of:

• Looks unwell

• Panicked

• Ashen, mottled, dusky

• Volume overload

• Extensive rales

• Killip class 3 or 4

• BiPap or mechanical ventilation

• Cold, clammy

• Acute alteration in mental status

• Urine output <30 mL/h

May include any of:

• Lactate ≥2

• Creatinine doubling

or

• >50% drop in GFR

• Increased LFTs

• Elevated BNP

May include any of:

• SBP <90 or MAP <60 or >30 mm Hg drop from baseline

and

• Drugs/device used to maintain BP above these targets

• Hemodynamics

• Cardiac index <2.2

• PCWP >15

• RAP/PCWP ≥0.8

• PAPI <1.85

• Cardiac power output ≤0.6

Stage D: Deteriorating/doom

Similar to category C but patient is getting worse

Failure to respond to initial interventions.

Any of stage C

Any of stage C

and

Deteriorating

Any of stage C

and

Requiring multiple pressors

or

Addition of mechanical circulatory support devices to maintain perfusion

"Sea Change"

Commenting on the statement for theheart.org | Medscape Cardiology, Emmanouil S. Brilakis, MD, PhD, director, Center for Complex Coronary Interventions, Minneapolis Heart Institute, noted that CS is "an area that is recognized more and more as needing new developments because we haven't had any improvement in mortality for many years and there is high mortality."

Brilakis, who was not involvement in developing the statement, noted that "one of the challenges we've had for a long time is there are different stages and types of CS and it is hard to compare outcomes and decide about treatment strategies if we are talking about the entire spectrum of CS."

Instead, "in talking about specific subgroups and subtypes it is easier to design protocols and design strategies, so what's nice about this [statement] is that it is a framework for identifying subgroups through the entire spectrum."

Baran suggested that the guideline "represents a sea change in how we look at CS because being on the same platform allows us to go forward with research trials."

He noted that the lack of clear definition has led to a 30-year period of research that has not improved survival rates.

"Our trials have mixed patients in several different stages, with some patients so sick that devices may not work, while in other stages, a properly chosen device may increase survival."

He expressed hope that, "as this classification system becomes standard language, trials with newer and better devices will be conducted and we would love to say 5 years from now that the survival has gotten better because we've gotten smarter about the right device at the right time."

Naidu added: "We call upon our colleagues in industry to look at various scenarios and revisit the RCTs [randomized clinical trials] to look at them for real stages, decide what interventions are safest and more efficacious for these therapies, and provide more uniformity for how we treat them globally."

No source of funding listed. Naidu and Baran report no conflicting interests. The other authors' disclosures are listed on the original paper. Brilakis receives consulting/speaker honoraria from Abbott Vascular, American Heart Association (associate editor of Circulation), Boston Scientific, Cardiovascular Innovations Foundation (Board of Directors), CSI, Elsevier, GE Healthcare, InfraRedx, Medtronic, and Teleflex. He receives research support from Regeneron and Siemens and is a shareholder in MHI Ventures. He is on the Board of Trustees of the Society of Cardiovascular Angiography and Interventions.

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